Adaptive product configuration for thermal insulation of buildings.

Fuerstner, Igor ; Anisic, Zoran

1. INTRODUCTION

Global competition is forcing companies to change their activities from a seller point of view towards a buyer point of view, what results in a drastic increase of product variety offered by enterprises, what is one of the main characteristic trends of modern economic system (Franke at al., 2001; Forza & Salvador, 2007). This approach alters the traditional product development and moves towards a two-stage model, the first, the realm of company/designer establishing the solution space and the second, that of customer as co-designer (Berger & Piller, 2003). This second stage fundamentally changes the role of the customer from consumer of a product, to a partner in a process of adding value (Reichwald et al., 2004). This alteration of traditional product development through the involvement of the customer into the configuration of the final product faces some obvious problems. The fundamental challenge is to avoid the abortion of the configuration process by the customer. In many cases, the customer aborts the configuration process by himself. Major problem areas include the lack of a customer desired option value regarding a specific attribute within the system as well as the inability of the customer to create definite preferences between certain option values. As a result, the customer aborts the configuration process and does not come up to the sales phase (Hansen et al., 2003). Customers usually only want the product alternatives that exactly fulfill their requirements. If too much of a choice is offered, customers can feel frustrated or confused and therefore incapable of making proper decisions (Blecker & Friedrich, 2006).

1.1 Outer thermo insulation

Outer thermo insulation of buildings is becoming more and more important, since energy resource prices have raised extensively in recent years, and environmental issues have become more relevant than ever before. Despite the widespread usage of thermo insulating materials in everyday practice, it can be noted that thermo insulation is often made self-initiated, without the proper knowledge about the materials, the technology, and the calculations needed to obtain the best results. This results in inadequate solutions, that can range from high installation costs and high consumption cost to short lifetime and insufficiency of the applied insulation. Several professional software packages exist on the market that deal with the problem, such as Bausoft Winwatt, Resfen, Casa Nova, etc., but they are developed only for users with proper knowledge about thermo insulation.

Therefore the developed configurator has to offer web based on-line instant results that are based on the latest results in research and practice; the results should be customized for each individual building; the configurator should be used by professionals, retailers and end users, with or without specific technical knowledge about thermo insulation and the results should be accurate enough.

2. CUSTOMER PROFILE CONFIGURATION

Based on the experience of a previous version of the developed configurator (Fuerstner & Anisic, 2009) it has been recognized that most of the problems had arisen due to the fact that some non-professional users had found the configurator too complex to use, while some of the professional users have found that the configurator lacked the possibility of defining exact and precise input parameters. Other problems included the need for more or less accurate results, as well as more or less time-consuming configuration. These problems were solved by identification of three different customer profiles:

* "Dummy" user;

* Intermediate user;

* Professional user.

"Dummy" user is a customer without proper technical knowledge about thermal insulation, or maybe a user with no need for highly accurate results, or a user with a need of a fast enough result, etc. Intermediate user is a customer with average technical knowledge about thermal insulation, but can also be a customer without proper technical knowledge about thermal insulation but with more time for completing the configuration process or with a need for more accurate result, etc. Professional user is a customer with proper knowledge about the problem of thermal insulation, can also be a customer with average technical knowledge about thermal insulation but with more time for completing the configuration process or with a need for more accurate result, etc.

To configure the appropriate customer profile, three initial questions are asked before the start of the configuration process:

* What is your estimate about your knowledge about thermal insulation?

* What are your needs considering the accuracy of the configuration results?

* How much time do you have for completing the configuration process?

The answers can be given in a form that is shown on fig. 1. The nature of the questions and the answers refer to the use of a non-crisp logic; therefore fuzzy logic is used to determine the appropriate customer profile. The configured customer profile is used in the configurator.

[FIGURE 1 OMITTED]

3. PROPOSED ALGORITHM

Research in the field of outer thermal insulation defines several rules that have to be considered when one wants to make the needed calculations. Different customer profiles that can be configured ask for different levels of project specific input parameters and constraints. Inputs for "dummy" user include only a limited number of required data regarding the building's structure, measures, materials and additional information as well as information about the building's surroundings for obtaining a satisfactory result. Inputs for intermediate user include data in more detail (Fuerstner & Anisic, 2009). The required information for professional user are defined and used by several professional software packages that exist on the market and will not be discussed in this paper.

Different structural parts of the building are taken into consideration separately by the proposed algorithm depending on the profile of the customer. The structural parts of the building are chosen based on necessary calculations and differences considering the choice of insulating materials defined by the manufacturer. Based on input parameters and constraints, several input calculations are made (Fuerstner & Anisic, 2009).

Based on the input calculations, for each structural part of the building the heat transmission coefficients are calculated. The calculation results are used as inputs for the calculation of total energy loss of the building. The heat transmission coefficients of the defined structural parts are used by the algorithm to define the needed insulating materials. After the needed insulating materials are offered, total energy loss of the building without proposed thermal insulation as well as with thermal insulation is calculated. Additionally the energy costs for different energy sources are calculated too. The offered insulating materials define the choice of additional materials such as the glue for the insulating material, screws, etc. The algorithm also enables the hand correction of insulating and additional material types, measures and amounts, based on which the total energy loss with hand picked materials is calculated. The final result is a bill of proposed material types and amounts, what can be used for purchasing.

4. RESULTS

The developed configurator is tested configuring the thermal insulation for existing buildings. Deviations from exact calculations for "dummy" user range from approximately 3.5% for calculations without thermal insulation to 18% for calculations with thermal insulation. Deviations for intermediate user range from approximately 1.5% for calculations without thermal insulation to 14% for calculations with thermal insulation.

5. CONCLUSIONS AND FUTURE RESEARCH

The results show that there are considerable differences between exact calculations and calculations obtained by the configurator, but the deviations of the results can be accepted if the nature of the research field is taken into consideration. In the case of "dummy" user the overall result can be used as a good starting point for more detailed calculations, while in the case of intermediate user the results don't differ too much from the results obtained by detailed calculations and can be used for purchasing. The configuration process in the case of the "dummy" user lasts about 2-3 minutes, for intermediate user the required time is about 5-10 minutes.

Experiences from retailers suggest that the idea of insulating a building is becoming more interesting and acceptable for the customers, when presented using the configurator, while end users suggest that there is further need to make the configurator more interesting. The results of the research and the gained experiences point towards several future research directions:

* Making the user interface more interesting by using as many visual and interactive elements as possible with real time multimedia help;

* Testing the new version of the configurator against the previous version on a significant statistical sample to get relevant information about the abortion level and the need for using different customer profiles;

* Definition of rules for taking into account the accepted solutions by previous customers of certain profile;

* Development of an intelligent decision making algorithm that can automatically adjust the solution that can lead to suggested solutions, which correspond to a greater extent to finally accepted results.

6. REFERENCES

Berger, C. & Piller, F. (2003). "Customers as Co-Designers", IEE Manufacturing Engineer, Vol. 82, No. 4, pp 42-46

Blecker, T. & Friedrich, G. (2006). Mass customization: challenges and solutions, Springer, ISBN: 978-0-387-32222-3, New York

Forza, C. & Salvador, F. (2007). Product Information Management for Mas Customization, Palgrave Macmillan, ISBN: 978-0-230-00682-9, Hampshire

Franke, H. J. & Firchau, N. L. (2001). Variantenvielfalt in Produkten und Prozessen--Erfarungen, Methoden und Instrum. zur erfolgreichen Beherrschung, Variety in Prod. and Processes--Experiences, Methods and Tools for Succ. Mastery, VDI-Berichte 1645, VDI-Verlag, Duesseldorf

Fuerstner, I. & Anisic, Z. (2009). Masterplast Intelligent Product Configurator--The New Approach in Thermo Insulation of Buildings. Proceedings of the International Scientific Conference MOTSP, pp 256-261, ISBN: 978-953-6313-09-9, Sibenik, Croatia, June 2009, FSB, Zagreb

Hansen, T., Scheer, C., Loos, P. (2003). Product Configurators in Electronic Commerce--Extension of the Configurator Concept--Towards Customer Recommendation, Proceedings of the 2nd Interdisciplinary World Congress on Mass Customization and Personalization (MCP), Technische Universitaet Muenchen Munich, Germany

Reichwald, R.; Seifert, S.; Walcher, D. & Piller, F. (2004). Customers as part of value webs: Towards a framework for webbed customer innovation tools, Proceedings of the 37th Annual Hawaii International Conference on System Sciences, Hawaii